Justification:
The species is endemic to central-eastern Europe (Carpathian Basin) and the northern Balkans; confirmed historical native records of the species are from Hungary, Slovakia, Croatia, Romania, and Serbia, however it appears that the species range has greatly diminished in recent years, with confirmed current records only known from the Danube floodplain in Hungary and Croatia (D. Bartha pers com 2014) and Serbia, with no recent records of the species from other former parts of its range, and it is considered possibly extinct in Slovakia and Romania.

In Hungary, the forest habitat area has been reduced due to industrialization. It is also impacted by a range of threats including forest clearance, forest management methods, development of plantations, declining groundwater levels, and grazing by wild animals (primarily deer). Based on available recent records of the species from Hungary and Croatia (D. Bartha pers. comm. 2014), the extent of occurrence of the species is estimated at 3,188 km2 and the area of occupancy at 128 km2 (the latter is assumed to be an under-estimate).This species is given a precautionary assessment of Endangered (A2ac; B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v)) in both Europe (and thus globally) and the EU 27, as it is threatened or has disappeared across a significant portion of its range over the past several decades, and continues to decline. Although the population decline can't be accurately estimated with the data available, it is thought to approach or exceed 50% in the past three generations, with causative declines in AOO, EOO, and habitat quality and extent.More information on the current population size, trends and the overall rate of decline is needed, and confirmation of the species presence and distribution in all parts of its former range. This species' habitat should be protected, unfavourable forest management methods improved, and alien species controlled to protect declining populations.

The species is endemic to central-eastern Europe (the Carpathian Basin) and the northern Balkans (Kurtto 2009, USDA 2013). Confirmed records of the species are from Hungary, Slovakia, Croatia, Romania and Serbia (G. Király pers. comm. 2013), however it appears that the species' range has greatly diminished in recent years, with current confirmed records known only from the Danube floodplain in Hungary and Croatia (D. Bartha pers. comm. 2014).In the northern Balkans, the species was known from the Danube basin, but is considered possibly extinct from here, with no recent records (D. Bartha pers. comm. 2014). Records from the Suva Planina Mountains in southeast Serbia (Papp and Erzberger 2009) require confirmation as they may be a misidentification of Crataegus pentagyna, as may records from Montenegro (D. Bartha pers. comm. 2014).

Hungary26 recent populations known, ten populations disappeared in the last 50 years, with recent records of the species restricted to along the Danube from Csepel Island to the Hungarian border.SlovakiaPossibly extinct; previously recorded from Bratislava (old data); currently only known in cultivation (Marhold and Hindák 2014).CroatiaThe species is present south from the Hungary-Croatia border along the Danube, in the Baranja and Eastern Slavonia regions; the southeastern population is near Ilok.SerbiaPreviously known from nine sites along the Danube, but considered likely to have been lost from some; there are recent records from the Begečka Jama wetlands (Danube Virtual Museum 2014), the Gornje Podunavlje Ramsar wetland (Stojnić 2007) and the Karapandža natural park (Márkus and Ŝakić undated); records of the species from the Suva Planina Mountains require confirmation.RomaniaFive sites were known along the Danube; possibly extinct, the eastern occurrence of the species was from Turnu Severin, with the last record from 1955.

Considered introduced (cultivated) in the Czech Republic (Danihelka et al. 2012). The species has in the past been misidentified as Crataegus pentagyna Waldst. & Kit. ex Willd., but this species lives in xerotherm forests, while C. nigra is found in alluvial forests (Bartha and Kerényi-Nagy 2010).

Based on available recent records of the species from Hungary and Croatia (D. Bartha pers. comm. 2014), the extent of occurrence of the species is estimated at 3,188 km2 and the area of occupancy at 128 km2 (the latter is assumed to be an under-estimate).

The total population size is unknown, but this species is uncommon across its remaining range; it is rare in Hungary and Croatia (M. Idzojtic pers. comm. 2014), and possibly extinct in the wild in Serbia, Romania, and Slovakia (Kurtto 2009, G. Király pers. comm. 2013).In Slovakiaits threat status is unclear according to Čeřovský et al. (1999); Marhold and Hindák (2014) list it as occurring only in cultivation in Slovakia. Although it is rare and fairly unknown in Croatia, it is naturally widespread along the Danube River in Baranja and Eastern Slavonia. The population is considered endangered and declining in Hungary, where a majority of the subpopulations are found (Baričevič et al. 2004, Király 2007, G. Király pers. comm. 2013).